The present invention relates to a band-saw machine of the type composed of a workpiece bench provided on a stand to hold a workpiece between clamping jaws and a machine head carrying an endless saw band and moveable relative to the stand for feeding the saw band into the workpiece.
Such a band-saw machine is disclosed, for example, in FRG Pat. No. 2,159,580 and counterpart U.S. Pat. No. 3,789,717. In this known band-saw machine the machine head is pivotably articulated to the machine stand and the clamping jaw nearer to the pivot mounting is displaceable, as is the saw band guide allocated thereto. The other clamping jaw is fixed to the frame, while the saw band guide allocated to this clamping jaw is fixed in position on the machine head.
This known band-saw structure solves the problem of guaranteeing adaptation of the displaceable band guide to the adjustable clamping jaw to facilitate handling, for which purpose the displacement movement of the band guide is synchronized with the adjusting movement of the displaceable clamping jaw.
For large workpiece cross sections as a rule, band saws with the saw head articulated pivotably on the machine frame are not used, but instead the machine head is arranged horizontally to be vertically displaceable in relation to the machine stand, either hydraulically or via setting spindles of column form. If the synchronization between the displaceable clamping jaw and the saw band guide allocated to it, as disclosed in the above-cited patents, is transferred to such band saws, then the carriage carrying the displaceable band guide and guided displaceably on the machine head must be very long, leading to corresponding tilting moments and vibration stresses, and therefore again compelling correspondingly massive and rigid formation of the carriage and its guide.